This invention relates to a novel method for treating lasing medium surfaces, often crystal surfaces, to reduce internal reflections which contribute to amplified spontaneous emission (ASE) losses. More particularly, this method uses a laser ablation treatment of lasing medium surfaces to reduce said internal reflections. As used herein. "ablation" refers to the physical process of material removal which may include a combination of melting, vaporization, sublimation or high temperature chemical reactions, among other processes.
The purpose of lasing medium surface treatment is to produce sufficient surface roughness to spread the internal reflection angles and to decrease the fraction of light which is internally reflected within the lasing medium, without weakening the mechanical strength of said lasing medium. Strength maintenance within the lasing medium is vitally important because the lasing medium must withstand high mechanical stresses created by thermal gradients which may arise during use.
In the past, acids;chemical etching has been utilized for treating lasing medium surfaces to reduce the internal reflections which contribute to amplified spontaneous emission (ASE) losses. However, acid/chemical etching is a lengthy process, and is often difficult to control. Furthermore, acid/chemical etching often results in insufficient surface roughness, thereby reducing the efficiency and power attainable from each lasing medium to an unacceptable level.
It is apparent from the above that there exists a need in the art for a method of treating lasing medium surfaces to reduce the internal reflection, which is fast, easily controlled, and produces sufficient surface roughing. It is a purpose of this invention, to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.